In the live music sphere, Las Vegas long was known as the place where acts went to die. From FrankSinatra and ElvisPresley on down, stars big and small spent their twilight years entertaining tourists on the Strip, a tradition that continued into the 2000s.

Credit CelineDion for turning the tide. Her A New Day show at the 4,000-seat Colosseum at Caesars Palace, which debuted in 2003, was the first to freshen up the residency from schmaltzy lounge act to theatrical extravaganza complete with smoke, fire and brimstone -- a model emulated by EltonJohn for his The Red Piano, which ran from 2004 through 2009, and The Million Dollar Piano, launched in 2011. Now BritneySpears' Piece of Me residency at Planet Hollywood kicks off Dec. 27.

Spears' arrival comes as the median age of the city's tourist demographic is dropping -- from 49 to 45 in the past four years -- thanks in large part to the EDM (electronic dance music) scene that has made Vegas its primary home. Such superstar DJs as Tiesto and Deadmau5 have settled into new state-of-the-art nightclubs like MGM's Hakkasan for their own residencies (the acts earn reported fees of up to $300,000 a night while clubs generate some $1.5 million in nightly drink sales) and will be competing with pop acts for tourist dollars. "It takes a pretty big shift in younger customers to move that age average down," says Caesars vp entertainment KurtMelien, who negotiated Spears' exclusive deal with PH (Spears is managed by Larry Rudolph and Adam Leber and represented by CAA). "We recognize those trends. They had a lot to do with us wanting a younger-skewing contemporary artist as a resident."

Spears will be raking in north of $30 million for her two-year stay, during which she's obligated to perform 50 shows a year (Dion's tally over five years and 700 shows is $400 million in box-office receipts; Spears' last North American tour grossed $38.3 million), and will get a percentage of ancillary businesses like merchandise. Planet Hollywood is using 117,000 square-feet of space to build a 4,600-seat theater designed to feel like a club -- complete with bottle service and dance floor -- and within moments of unveiling the exclusive run had plastered the pop star's face all over town.

The all-out advertising assault -- tops of taxi cabs, billboards, jumbotrons on the Las Vegas Strip -- is a perk of being the new act in town (just ask FaithHill and TimMcGraw, who recently extended their Soul2Soul stint at the Venetian), and, all told, can add up to tens of millions of promotional dollars spent, but settling down for a Sin City stretch has a more tangible purpose behind it: stability.

"It’s no secret that bands are no longer sitting on their couches collecting royalty checks," says BobbyReynolds, vp booking at AEG Live, Las Vegas. Speaking of Motley Crue's first residency at the Hard Rock Hotel & Casino that began in February 2012, he explains: "They played to their fans in an intimate room and sold over 36,000 tickets in 12 shows."

Indeed, the main advantage to a residency is the cost. "The biggest line item on a tour is trucking and transportation," which includes fuel and labor, says JohnnyWright, manager for JustinTimberlake and the JonasBrothers.

With the money saved, the artist can invest in their Vegas show. "You can do bigger things by not having to tear it down every night, drive 300 miles and build it back up," says Crue frontman VinceNeil. The band is now on its second stint at the Hard Rock. "On the last run, it was basically a circus -- we had little people, flying people … a cast of, like, 50 performers. You can't take that many people around. It's not cost effective."

On the other hand, the singer adds: “It’s really not as profitable because we put so much money into making this thing so big. This is Vegas and you want people to talk about it, so after the first show, we watch the tapes back and go, ‘It needs more fire here, we need more of that here…’ Which, every time you say ‘we need’ -- dollar signs.”

Still, another plus to staying put in Vegas: The world comes to you. As Neil explains: "Every night, I ask the audience, 'Who's from out of town?' And 99 percent of the people raise their hands."

For Spears, who's circled the globe multiple times, "The idea was to create this epicenter for her fans to travel to," says Melien.

So far, ticket sales for Piece of Me have been swift, with $500 VIP packages selling out (a meet-and-greet with Spears will run fans around $2,500). It all bodes well for "another evolution of Vegas," Caesars' Melien adds of the city's plan to attract more music stars. (Worth noting: Those hoping for a state income-tax break would have to establish permanent residence in Nevada; Doing so would save Spears, who lives in California, at least $3 million, according to one CPA's estimate.)

Key to the destination concert, however, is having the repertoire for a 90-minute show. Some surmise that R&B singer ToniBraxton didn't when her two-year contract with the Flamingo was canceled in 2008. In Spears' case, 21 hits along with songs from her new album, due out Dec. 3, will function as a musical "retrospective of iconic moments of her life." Albeit, a sanitized version, lest we forget Spears married a high-school pal at a drive-through chapel just three miles down the road from Planet Hollywood in 2004 (50 hours later, the union was annulled). Then again, where else can you distort reality if not Vegas?